Powder Hopper for the Gravity-Driven Feeding of Powdered Electrode Precursor Material Into a Nip of a Dry Electrode Caldender, Corresponding Assembly, and Corresponding Method

Abstract

The invention relates to a powder hopper (101) for the gravity-driven feeding of powdered electrode precursor material (102) into a nip of a dry electrode calendar (2), said powder hopper comprising: a powder feed opening (105) for feeding powdered electrode precursor material (102) into the powder hopper; and a powder outlet opening (106) for metering the powdered electrode precursor material from the powder hopper into a nip, the cross-section of the powder hopper tapering between the powder feed opening and the powder outlet opening, and the powder hopper having a level detection means (103) for detecting the powder level of the powder hopper. The invention also relates to: a corresponding assembly consisting of a powder hopper and a first and a second roller that form a nip; and a method for operating a powder hopper.

1 . A powder hopper for gravity-driven feeding of powdered electrode precursor material into a nip of a dry electrode calender, having a powder feed opening for feeding powdered electrode precursor material into the powder hopper and a powder outlet opening for metering the powdered electrode precursor material from the powder hopper into a nip, wherein the cross section of the powder hopper tapers between the powder feed opening and the powder outlet opening, characterized in that the powder hopper has a level detection device for determining the powder level of the powder hopper. 
     
     
         2 . The powder hopper according to  claim 1 , which furthermore has a weight detection device for determining the weight of powder in the powder hopper. 
     
     
         3 . The powder hopper according to  claim 2 , wherein the weight detection device has at least one load cell on which the powder hopper is supported. 
     
     
         4 . The powder hopper according to  claim 3 , wherein the powder hopper has at least one first and at least one second load cell and at least two support tabs which project laterally on opposite sides of the powder hopper, wherein the powder hopper is supported on the at least one first load cell via one of the support tabs and on the at least one second load cell via the other opposite support tab. 
     
     
         5 . The powder hopper according to  claim 1 , wherein the powder hopper has a width (B) extending transversely to the nip and a length (L) extending along the nip, wherein the width (B) of the powder hopper decreases between the powder feed opening and the powder outlet opening and the length (L) of the powder hopper between the powder feed opening and the powder outlet opening is constant. 
     
     
         6 . The powder hopper according to  claim 1 , wherein the fill level detection device has at least one first fill level sensor in the area above the powder outlet opening. 
     
     
         7 . The powder hopper according to  claim 1 , wherein the fill level detection device has at least one second fill level sensor in the area below the powder feed opening. 
     
     
         8 . The powder hopper according to  claim 1 , wherein the level detection device comprises at least one capacitive fill level sensor. 
     
     
         9 . The powder hopper according to  claim 6 , wherein the fill level sensor has a plurality of sensor units distributed over the length of a side wall of the powder hopper and arranged at essentially the same height. 
     
     
         10 . The powder hopper according to  claim 9 , wherein the side wall of the powder hopper having the plurality of sensor units is arranged substantially vertically. 
     
     
         11 . The powder hopper according to  claim 10 , wherein the first fill level sensor has a first plurality of sensor units distributed over the length (L) of a first substantially vertical side wall of the powder hopper and arranged at substantially the same height, and wherein the second fill level sensor has a second plurality of sensor units distributed over the length (L) of a second substantially vertical side wall of the powder hopper and arranged at substantially the same height, wherein an inclined side wall connecting the first and the second side wall and tapering the width (B) of the powder hopper in the direction of the powder outlet opening is arranged between the first and the second side wall. 
     
     
         12 . The powder hopper according to  claim 1 , wherein the level detection device comprises at least one optical fill level sensor. 
     
     
         13 . The powder hopper according to  claim 12 , wherein the optical fill level sensor is directed at the interior of the powder hopper spaced apart from the powder hopper through the powder feed opening. 
     
     
         14 . The powder hopper according to  claim 12 , wherein the detection range of the optical fill level sensor comprises at least the entire length (L) and the entire width (B) of the powder hopper. 
     
     
         15 . The powder hopper according to  claim 12 , wherein the optical fill level sensor is configured to detect the filling volume of the powder hopper with powdered electrode precursor material. 
     
     
         16 . The powder hopper according to  claim 12 , wherein the optical fill level sensor is furthermore configured to detect powder fill levels that are unevenly distributed over the length (L) of the powder hopper. 
     
     
         17 . An assembly comprising a powder hopper according to  claim 1  and a first and a second roll forming a nip, wherein the powder outlet opening of the powder hopper is arranged above and along the nip, so that the powdered electrode precursor material can be metered into the nip over this entire length of the powder outlet opening. 
     
     
         18 . The assembly according to  claim 17 , wherein the assembly furthermore has a feed conveyor arranged above the powder hopper, by means of which powdered electrode precursor material can be conveyed into the nip. 
     
     
         19 . The assembly according to  claim 18 , wherein the conveying speed of the feed conveyor is regulated depending on the powder density determined in the powder hopper, wherein the powder density is calculated on the basis of the powder filling height determined via the fill level detection device and the powder mass determined via the weight detection device. 
     
     
         20 . The assembly according to  claim 19 , wherein the conveying speed is increased when the calculated powder density exceeds a first threshold value of a target range, and wherein the conveying speed is slowed down when the calculated powder density falls below a second threshold value of the target range. 
     
     
         21 . The assembly according to  claim 1 , in which the powder hopper is conditioned on its inner sides, along which the powder is guided by gravity, to reduce friction with respect to the powder, preferably a coating or has an inlay having a low coefficient of friction in relation to the powder. 
     
     
         22 . The assembly according to  claim 1 , in which the powder outlet opening has a gap aperture tapering in the direction of the nip and in the direction perpendicular to the axis of rotation of the rolls forming the nip, which is designed to meter the powder directly into the nip. 
     
     
         23 . A method for operating a powder hopper, comprising the following steps:
 Determining the fill level of the powder hopper with powdered electrode precursor material;   Determining the weight of the powdered electrode precursor material located in the powder hopper;   Calculating the density of the powdered electrode precursor material located in the powder hopper from the determined fill level and the determined weight;   Regulating a flow of powdered electrode material conveyed into the powder hopper.   
     
     
         24 . The method according to  claim 21 , wherein regulating the flow of powdered electrode material fed into the powder hopper comprises regulating a conveying speed of a feed conveyor connected upstream of the powder hopper. 
     
     
         25 . The method according to  claim 21 , wherein determining the fill level of the powder hopper comprises determining using a capacitive and/or optical sensor. 
     
     
         26 . The method according to  claim 21 , wherein determining the fill level of the powder hopper can comprise determining the presence of powdered electrode precursor material on a first powder hopper level and determining the presence of powdered electrode precursor material on a second powder hopper level, wherein the height of the first powder hopper level can differ from the height of the second powder hopper level. 
     
     
         27 . The method according to  claim 21 , wherein determining the weight of the powdered electrode precursor material located in the powder hopper comprises weighing the powder hopper minus the powder hopper weight.